Hitherto, for producing an electrode for a semiconductor cubic system boron nitride (hereinafter referred to as "cBN"), a silver paste is used as described in e.g., in Appl. Phys. Lett., vol. 53(11), Sept. 12, 1988, pp. 962-964 but a technique of producing an ohmic electrode for a semiconductor cBN has not yet been developed at present.
In a conventional process for producing an electrode using a silver paste, a contact resistance is large and also the resistance characteristics at passing electric current are unstable. Furthermore, a silver paste shows a poor wetting property with cBN as well as there is a problem that the adhesive strength is weak, whereby the electrode is liable to be separated from the crystal. Accordingly, it is difficult to produce a semiconductor using a cBN crystal.